Ask Sail: Staysail Loads

I would like to add an inner forestay to my Hughes Columbia 40. The sail for this is 350 square feet. What safe working load would I need for an exit block for the mast as well as jib tracks and leads?
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By using sail area and expected wind speeds, you can easily estimate headsail loads

By using sail area and expected wind speeds, you can easily estimate headsail loads

Larry Schnell, Cooperstown, NY
Q: I would like to add an inner forestay to my Hughes Columbia 40. The sail for this is 350 square feet. What safe working load would I need for an exit block for the mast as well as jib tracks and leads?

Win Fowler Replies
A: The load on a sail is proportional to the sail area times windspeed squared. The formula is: (sail area [in ft2] x windspeed2 [in knots]) coefficient = load. In our shop we use a coefficient of 0.00431. For a 350ft2 sail in 30 knots this yields a load of 1,358lb. In 40 knots of wind, the load climbs to 2,414lb. We assume that this is the load on both the sheet and the halyard. I would think a safe working load of 2,500lb would be pretty good.

HR-win-fowler2d_0

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